Data polling using a chain sleep technique

ABSTRACT

Examples of data polling using a chain sleep technique are disclosed. In one example, a computer-implemented method includes: computing a least common multiplier (LCM) based on a polling time for each of a plurality of devices deployed in a well operation to be polled; generating a sequence of polling elements, wherein each of the polling elements represents a multiple of the polling time for each of the plurality of devices, wherein the sequence of polling elements begins with the lowest polling time and ends with the LCM; sorting the sequence of polling elements from lowest value to highest value as an ordered list; calculating a distance between each of the polling elements of the ordered list; generating a polling chain based on the ordered list and the distance between each of the polling elements; and polling the plurality of devices in the well operation based on the polling chain.

BACKGROUND

The present disclosure relates generally to well operations and, moreparticularly, to data polling using a chain sleep technique.

Device polling is useful for collecting data from and controllingdevices used in a well operation (or across multiple well operations).For example, it may be desirable to collect data from various devicessuch as artificial lift systems, submersible pumps, and the like. Thedata may be collected periodically, such as every few seconds, minutes,or hours, depending on the type of device and/or the type of datacollected. In some implementations, virtual servers and/or cloudservices may be used in collecting and storing the data.

BRIEF SUMMARY

According to examples of the present disclosure, techniques includingmethods, systems, and/or computer program products for a data pollingusing a chain sleep are provided. An example computer-implemented methodmay include: computing, by a processing device, a least commonmultiplier (LCM) based on a polling time for each of a plurality ofdevices deployed in a well operation to be polled; generating, by theprocessing device, a sequence of polling elements, wherein each of thepolling elements represents a multiple of the polling time for each ofthe plurality of devices, wherein the sequence of polling elementsbegins with the lowest polling time and ends with the LCM; sorting, bythe processing device, the sequence of polling elements from lowestvalue to highest value as an ordered list; calculating, by theprocessing device, a distance between each of the polling elements ofthe ordered list; generating, by the processing device, a polling chainbased on the ordered list and the distance between each of the pollingelements; and polling, by the processing device, the plurality ofdevices in the well operation based on the polling chain.

Additional features and advantages are realized through the techniquesof the present disclosure. Other aspects are described in detail hereinand are considered a part of the disclosure. For a better understandingof the present disclosure with the advantages and the features, refer tothe following description and to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features, and advantagesthereof, are apparent from the following detailed description taken inconjunction with the accompanying drawings in which:

FIG. 1 illustrates a block diagram of a processing system generating ascript for performing a well operation job according to aspects of thepresent disclosure;

FIGS. 2A, 2B, 2C, and 2D illustrate examples of polling chain datastructures according to aspects of the present disclosure; and

FIG. 3 illustrates a block diagram of a processing system forimplementing the techniques described herein according to aspects of thepresent disclosure.

DETAILED DESCRIPTION

Data polling may be used to collect data from various devices in a welloperation. Each of these devices may provide one or more types of data.Existing data polling techniques are limited in the number of devicesthat can be polled. The present disclosure addresses the challenge ofthe technical limitation on the number of simultaneous physical devicesthat can be reliably accessed and controlled per server and theresulting high cost. In particular, the present disclosure provides adata polling device with a dynamic scheduling mechanism using anefficient algorithm and data structure to handle more devicessimultaneous than existing techniques.

The chain sleep technique disclosed herein makes use of a least commonmultiplier to form a chain of active trigger nodes that trigger apolling request and are linked with inactive sleep nodes that containthe next poll distance (i.e., a sleep duration). This gives preferencesfor other active instances to effectively poll the devices. The chainsleep technique handles the polling triggers without the use of anydatabase and/or file system by using a chain-like data structure that ismade of the active trigger nodes and inactive sleep nodes. Activetrigger nodes utilize processing time of a processing device forprocessing a task. Sleep nodes connected between two consecutive activetrigger nodes and provide processing priority to other active instances.According to aspects of the present disclosure, the chain sleeptechnique is capable of handling dynamic polling at multiple intervalsin an effective and efficient manner to poll data from multiple devices,such as devices used at a well operation.

Example embodiments of the disclosure include or yield various technicalfeatures, technical effects, and/or improvements to technology. Exampleembodiments of the disclosure provide for data polling using a chainsleep technique. The chain sleep technique described herein provides forthe efficient collection of data from devices used in a well operation.These aspects of the disclosure constitute technical features that yieldthe technical effect of enabling many nodes to be polled by a singleprocessing system. As a result of these technical features and technicaleffects, the present chain sleep technique may provide a ten-foldincrease in the number of devices that may be polled in comparison toexisting techniques. Moreover, the data collected using the chain sleeptechnique described herein can be used to control the devices from whichthe data is collected. For example, it may be determined that a devicesuch as a submersible pump should increase pressure based on collecteddata to increase production levels. It should be appreciated that theabove examples of technical features, technical effects, andimprovements to technology of example embodiments of the disclosure aremerely illustrative and not exhaustive.

FIG. 1 illustrates a flow diagram of a method 100 for data polling usinga chain sleep technique according to aspects of the present disclosure.The method 100 may be performed by any suitable processing system, suchas the processing system 20 of FIG. 3, or by another suitable processingsystem.

Devices used in a well operation, such as artificial lift systems,submersible pumps, and other equipment, may be polled to collect dataabout the devices. By polling the devices to collect data, the welloperation can be monitored and the devices can be controlled. Forexample, if data indicates that a pump is not pumping at a high enoughrate, the rate may be increased, such as by an automated system ortechnician.

The polling time for each device (or for each of a plurality of sensorswithin the device) represents a time that each device is to be polled.For example, a device (or sensor) may be polled every three seconds,every five seconds, every two minutes, every fifteen minutes, everyhour, every three hours, etc. It should be appreciated that otherpolling times are possible and within the scope of the presentdisclosure.

At block 102, the method 100 includes computing, by a processing device,a least common multiplier based on a polling time for each of aplurality of devices deployed in a well operation to be polled. The LCMof any combination of numbers (e.g., polling times) is perfectlydivisible by all of the members which is used to compute the LCM. Forexample, the LCM of the numbers 3 and 4 is 12, which is perfectlydivisible by both 3 and 4. Similarly, the LCM of the numbers 3, 6, and 9is 18, which is perfectly divisible by 3, 6, and 9.

At block 104, the method 100 includes generating, by the processingdevice, a sequence of polling elements. Each of the polling elementsrepresents a multiple of the polling time for each of the plurality ofdevices. The sequence of polling elements begins with the lowest pollingtime and ends with the LCM. Using the example with polling times of 3and 4 with an LCM of 12, the polling elements for 3 is 3, 6, 9, and 12and the polling elements for 4 is 4, 8, and 12.

At block 106, the method 100 includes sorting, by the processing device,the sequence of polling elements from lowest value to highest value asan ordered list. Using the polling times of 3 (for device 1) and 4 (fordevice 2) with polling elements 3, 6, 9, 12 and 4, 8, 12 respectively,the sorted sequence is 3, 4, 6, 8, 9, 12, 12. It should be appreciatedthat the value 12 is repeated as it is an element in the set of pollingtimes for both 3 and 4. FIG. 2A illustrates a block diagram of a pollingchain data structure 200 of the sorted sequences of polling elements fordevices 1 and 2 according to aspects of the present disclosure. Thehexagon elements represent device 1's polling elements and the squareelements represent device 2's polling elements.

Continuing with reference to FIG. 1, at block 108, the method 100includes calculating, by the processing device, a distance between eachof the polling elements of the ordered list. For example, using thesorted sequence 3, 4, 6, 8, 9, 12, 12, the distance between 3 and 4 is1, the distance between 4 and 6 is 2, the distance between 6 and 8 is 2,the distance between 8 and 9 is one, the distance between 9 and 12 is 3,and the distance between 12 and 12 is 0. It should also be appreciatedthat the distance between the highest value (12) and the lowest value(3) is calculated as 3, because once the last polling occurs at 12, thepolling restarts and the lowest value is 3. It should be appreciatedthat the distance represents an amount of delay (or sleep) time betweenpolling elements.

FIG. 2B illustrates a block diagram of a polling chain data structure201 of the sorted sequences of polling elements for devices 1 and 2including the calculated distances between each polling elementaccording to aspects of the present disclosure.

Continuing with reference to FIG. 1, at block 110, the method 100includes generating, by the processing device, a polling chain based onthe ordered list and the distance between each of the polling elements.The polling chain includes the polling elements, in order from lowest tohighest, and the respective distances between each of the pollingelements, with the last (highest) polling element linking back to thefirst (lowest) polling element. FIG. 2B illustrates a block diagram of apolling chain data structure 201 of the sorted sequences of pollingelements for devices 1 and 2 including the calculated distances betweeneach polling element according to aspects of the present disclosure.

FIG. 2C illustrates a block diagram of a polling chain data structure202 including the ordered list and the distance between each of thepolling elements according to aspects of the present disclosure. In theexample of FIG. 2C, adjacent polling elements are filtered to combinepolling elements with zero distances there between. Adjacent pollingelements are indicated by a zero distance between polling elements.These adjacent polling elements are polled concurrently. FIG. 2Dillustrates a block diagram of a polling chain data structure 203 thatincludes a designated start node. The polling chain includes each of thepolling elements, and each of the polling elements is separated by asleep element. It should be appreciated that the sleep element is themeasured distance between two adjacent nodes and represents an amount oftime (e.g., 3 seconds, 1 hour, etc.).

Continuing with reference to FIG. 1, at block 112, the method 100includes polling, by the processing device, the plurality of devices inthe well operation based on the polling chain. That is, the method 100includes polling each of the plurality of devices at the times indicatedby the polling elements for each of the devices and waiting the distancedelay between each of the polling elements where no polling occurs. Nopolling occurs at times corresponding to the sleep elements whilepolling does occur at times corresponding to the polling elements.

Additional processes also may be included. For example, the method 100may include generating a report. The report may include simulated valuesfor the operating parameters, such as (operating time, maximum boreholetemperature, maximum hydrostatic pressure, maximum tension on the cable,amount of additional pull available when trying to free a stuck tool,minimum tension on the cable, maximum downhole tools temperature,maximum mechanical stress on the downhole tool housings, maximumproduction rate acceptable, pressure swab and surge effects and anyother outcome resulting from the execution of the operation planned).The report may also include statements corresponding to the values thatdescribe how well each value of the operating parameters complies with aset of pre-defined target ranges for each of the operating parameters.It should be understood that the processes depicted in FIG. 1 representillustrations, and that other processes may be added or existingprocesses may be removed, modified, or rearranged without departing fromthe scope and spirit of the present disclosure.

It is understood in advance that the present disclosure is capable ofbeing implemented in conjunction with any other type of computingenvironment now known or later developed. For example, FIG. 3illustrates a block diagram of a processing system 20 for implementingthe techniques described herein. In examples, processing system 20 hasone or more central processing units (processors) 21 a, 21 b, 21 c, etc.(collectively or generically referred to as processor(s) 21 and/or asprocessing device(s)). In aspects of the present disclosure, eachprocessor 21 may include a reduced instruction set computer (RISC)microprocessor. Processors 21 are coupled to system memory (e.g., randomaccess memory (RAM) 24) and various other components via a system bus33. Read only memory (ROM) 22 is coupled to system bus 33 and mayinclude a basic input/output system (BIOS), which controls certain basicfunctions of processing system 20.

Further illustrated are an input/output (I/O) adapter 27 and acommunications adapter 26 coupled to system bus 33. I/O adapter 27 maybe a small computer system interface (SCSI) adapter that communicateswith a hard disk 23 and/or a tape storage drive 25 or any other similarcomponent. I/O adapter 27, hard disk 23, and tape storage device 25 arecollectively referred to herein as mass storage 34. Operating system 40for execution on processing system 20 may be stored in mass storage 34.A network adapter 26 interconnects system bus 33 with an outside network36 enabling processing system 20 to communicate with other such systems.

A display (e.g., a display monitor) 35 is connected to system bus 33 bydisplay adaptor 32, which may include a graphics adapter to improve theperformance of graphics intensive applications and a video controller.In one aspect of the present disclosure, adapters 26, 27, and/or 32 maybe connected to one or more I/O busses that are connected to system bus33 via an intermediate bus bridge (not shown). Suitable I/O buses forconnecting peripheral devices such as hard disk controllers, networkadapters, and graphics adapters typically include common protocols, suchas the Peripheral Component Interconnect (PCI). Additional input/outputdevices are shown as connected to system bus 33 via user interfaceadapter 28 and display adapter 32. A keyboard 29, mouse 30, and speaker31 may be interconnected to system bus 33 via user interface adapter 28,which may include, for example, a Super I/O chip integrating multipledevice adapters into a single integrated circuit.

In some aspects of the present disclosure, processing system 20 includesa graphics processing unit 37. Graphics processing unit 37 is aspecialized electronic circuit designed to manipulate and alter memoryto accelerate the creation of images in a frame buffer intended foroutput to a display. In general, graphics processing unit 37 is veryefficient at manipulating computer graphics and image processing, andhas a highly parallel structure that makes it more effective thangeneral-purpose CPUs for algorithms where processing of large blocks ofdata is done in parallel.

Thus, as configured herein, processing system 20 includes processingcapability in the form of processors 21, storage capability includingsystem memory (e.g., RAM 24), and mass storage 34, input means such askeyboard 29 and mouse 30, and output capability including speaker 31 anddisplay 35. In some aspects of the present disclosure, a portion ofsystem memory (e.g., RAM 24) and mass storage 34 collectively store anoperating system to coordinate the functions of the various componentsshown in processing system 20.

The present techniques may be implemented as a system, a method, and/ora computer program product. The computer program product may include acomputer readable storage medium (or media) having computer readableprogram instructions thereon for causing a processor to carry outaspects of the present disclosure.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present disclosure may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some examples, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present disclosure.

Aspects of the present disclosure are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to aspects of thepresent disclosure. It will be understood that each block of theflowchart illustrations and/or block diagrams, and combinations ofblocks in the flowchart illustrations and/or block diagrams, can beimplemented by computer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousaspects of the present disclosure. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

The descriptions of the various examples of the present disclosure havebeen presented for purposes of illustration, but are not intended to beexhaustive or limited to the embodiments disclosed. Many modificationsand variations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the described techniques.The terminology used herein was chosen to best explain the principles ofthe present techniques, the practical application or technicalimprovement over technologies found in the marketplace, or to enableothers of ordinary skill in the art to understand the techniquesdisclosed herein.

Set forth below are some embodiments of the foregoing disclosure:

Embodiment 1

A computer-implemented method for data polling using a chain sleeptechnique, the method comprising: computing, by a processing device, aleast common multiplier (LCM) based on a polling time for each of aplurality of devices deployed in a well operation to be polled;generating, by the processing device, a sequence of polling elements,wherein each of the polling elements represents a multiple of thepolling time for each of the plurality of devices, wherein the sequenceof polling elements begins with the lowest polling time and ends withthe LCM; sorting, by the processing device, the sequence of pollingelements from lowest value to highest value as an ordered list;calculating, by the processing device, a distance between each of thepolling elements of the ordered list; generating, by the processingdevice, a polling chain based on the ordered list and the distancebetween each of the polling elements; and polling, by the processingdevice, the plurality of devices in the well operation based on thepolling chain.

Embodiment 2

The method of any prior embodiment, wherein the polling chain compriseseach of the polling elements, and wherein each of the polling elementsis separated by a sleep element.

Embodiment 3

The method of any prior embodiment, wherein the sleep element representsthe distance between each of the polling elements, and wherein thedistance is a length of time.

Embodiment 4

The method of any prior embodiment, further comprising filtering thepolling chain to remove duplicate polling elements.

Embodiment 5

The method of any prior embodiment, wherein the polling elementindicates which of the plurality of devices is to be polled.

Embodiment 6

The method of any prior embodiment, wherein the polling occurs at timescorresponding to the polling elements.

Embodiment 7

The method of any prior embodiment, wherein no polling occurs at timescorresponding to the sleep elements.

Embodiment 8

The method of any prior embodiment, wherein the polling chain furthercomprises a designated start device.

Embodiment 9

The method of any prior embodiment, wherein the start device is thelowest value polling element.

Embodiment 10

The method of any prior embodiment, wherein the polling begins at thedesignated start device and continues to the highest value pollingelement.

Embodiment 11

The method of any prior embodiment, wherein the polling returns to thestart device after polling the highest value polling element and repeatsthe polling.

Embodiment 12

The method of any prior embodiment, further comprising controlling atleast one of the devices used in the well operation based on datacollected during the polling.

Embodiment 13

A system for deployment risk management, the system comprising: a memoryhaving computer readable instructions; and a processing device forexecuting the computer readable instructions, the computer readableinstructions comprising: polling a plurality of devices using a pollingchain generated based on a least common multiplier of a polling time foreach of a plurality of devices deployed in a well operation; andcontrolling at least one of the plurality of devices used in the welloperation based on data collected during the polling.

Embodiment 14

The system of any prior embodiment, wherein the polling chain comprisespolling elements, and wherein each of the polling elements is separatedby a sleep element.

Embodiment 15

The system of any prior embodiment, wherein the sleep element representsthe distance between each of the polling elements, and wherein thedistance is a length of time.

Embodiment 16

The system of any prior embodiment, wherein the polling elementindicates which of the plurality of devices is to be polled, wherein thepolling occurs at times corresponding to the polling elements, whereinno polling occurs at times corresponding to the sleep elements.

While one or more embodiments have been shown and described,modifications and substitutions may be made thereto without departingfrom the spirit and scope of the invention. Accordingly, it is to beunderstood that the present invention has been described by way ofillustrations and not limitation.

What is claimed is:
 1. A computer-implemented method for data pollingusing a chain sleep technique, the method comprising: computing, by aprocessing device, a least common multiplier (LCM) based on a pollingtime for each of a plurality of devices deployed in a well operation tobe polled; generating, by the processing device, a sequence of pollingelements, wherein each of the polling elements represents a multiple ofthe polling time for each of the plurality of devices, wherein thesequence of polling elements begins with the lowest polling time andends with the LCM; sorting, by the processing device, the sequence ofpolling elements from lowest value to highest value as an ordered list;calculating, by the processing device, a distance between each of thepolling elements of the ordered list; generating, by the processingdevice, a polling chain based on the ordered list and the distancebetween each of the polling elements; and polling, by the processingdevice, the plurality of devices in the well operation based on thepolling chain.
 2. The method of claim 1, wherein the polling chaincomprises each of the polling elements, and wherein each of the pollingelements is separated by a sleep element.
 3. The method of claim 1,wherein the sleep element represents the distance between each of thepolling elements, and wherein the distance is a length of time.
 4. Themethod of claim 1, further comprising filtering the polling chain toremove duplicate polling elements.
 5. The method of claim 1, wherein thepolling element indicates which of the plurality of devices is to bepolled.
 6. The method of claim 1, wherein the polling occurs at timescorresponding to the polling elements.
 7. The method of claim 2, whereinno polling occurs at times corresponding to the sleep elements.
 8. Themethod of claim 1, wherein the polling chain further comprises adesignated start device.
 9. The method of claim 8, wherein the startdevice is the lowest value polling element.
 10. The method of claim 9,wherein the polling begins at the designated start device and continuesto the highest value polling element.
 11. The method of claim 10,wherein the polling returns to the start device after polling thehighest value polling element and repeats the polling.
 12. The method ofclaim 10, further comprising controlling at least one of the devicesused in the well operation based on data collected during the polling.13. A system for deployment risk management, the system comprising: amemory having computer readable instructions; and a processing devicefor executing the computer readable instructions, the computer readableinstructions comprising: polling a plurality of devices using a pollingchain generated based on a least common multiplier of a polling time foreach of a plurality of devices deployed in a well operation; andcontrolling at least one of the plurality of devices used in the welloperation based on data collected during the polling.
 14. The system ofclaim 13, wherein the polling chain comprises polling elements, andwherein each of the polling elements is separated by a sleep element.15. The system of claim 13, wherein the sleep element represents thedistance between each of the polling elements, and wherein the distanceis a length of time.
 16. The system of claim 13, wherein the pollingelement indicates which of the plurality of devices is to be polled,wherein the polling occurs at times corresponding to the pollingelements, wherein no polling occurs at times corresponding to the sleepelements.